The question on the Maronite or Latin grandchild is an interesting one, but in retrospect uncomplicated.

At the time of the birth of the children of the grandfather (who was then Muslim, non-Catholic) and the grandmother (Latin Catholic), the children of that marriage would all be ascribed to the Latin Church.

Then their children (including the author of the post) would also be ascribed to the Latin Church at their respective birth.

The fact that the grandfather later became Catholic would probably ascribe him to the Maronite Catholic Church, regardless which church his baptism ceremony was held. So at this point the Catholic baptism of the grandfather, which was probably held in a Latin Church, had the effect of ascribing him to the Maronite Catholic Church, because of his heritage.

At that point, the children of the grandfather, along with the grandchildren, still remained Latin Catholic.

Now, if the grandchild (the poster) feels drawn to the Maronite Catholic Church, then it would be spiritually fitting for her to attend the Maronite Divine Liturgy on a regular basis. If after a year or two she felt that this is in fact the Catholic Church that is spiritually her own, she could then begin the formal process of Change of Church. During this process she would best be advised to have guidance from a competent spiritual director.